Elevator apparatus



Jam 21, 1936-. M. B. MCLAUTHLIN ELEVATOR APPARATUS Filed May 14, 1952 3 Sheets-Sheet 1 Jan. 21, 1936- M. B. MCLAUTH'LiN' ELEvA'roR AlPARA'TUs Filed May 14, 1932 3 Sheets-Sheet 2 Jan. 21, 193 M. B. MCLAUTHLiN 2,028,405

ELEvAToR APPARATUS Filed May`14, 1932 5 sheets-sheet 5 Patented Jan. 21, 1936 @PATENT osFFzifcE .ELEvAToR APPARATUS Y `Martin"B. McLauthlinfMaldemMass Application Mayf 14, 1932;. Serial -No.:611,299

4, Claims.

My `invention is an; elevator '.apparatusfarid may .be embodiedinfa dumbwaiter. .l It has for itsuobj ect ftofimprove `.the L construction .andfoperation ot elevator apparatus.

The advantages of the. hydraulic .dumbwaiter s for; manyv situationsizare.; generally; acknowledged but its: use. has been restricted .onsaccount ofthe vcost of instal-lation.' :.'Iihe only 'well developed type of hydraulic dumbwaiter heretofore provposed' was .the ".directplunger type .wherein the carfwas mounted upon` the upper end of -a plunger =Wh0se lower endportion was housed within a well :101': icylllde.

is comparatively .expensive kto Yinstall and to :operate -Another objection to hydraulic dumbwaiterkapparatusyhasbeen the liabilityy of leakage oi-water fand: the :messiness: and damage resultingl there- `from.

Atl thezpresentttime thereis a rdemand'ffora -simple,zlabor;'saying,. fool-proof :and economical, power-operated dumbwaiter for lunch rooms, --soda fountains,` restaurants, markets andl other stores, z etc., particularly of 'the Yminderecounter type, for servicewbetween' two floors of =a2 building was, or..eXa-mple, betweenthe basementvand street ,oor.

' The principal object of my invention is to pro- ,videianfinexpensive reliablafand cientv-hya-draulic :dumbwaiter -.apparatus @Whose constructionxiwill obviate the `objections aboveI noted and vwhichzwill be'particularly adapted for use in situationslsuchas' those just referredto.

z-'Iorthis endV I `have :developed and constructed a `hydraulic dumbwaiter .apparatus l includingr a I noveltcoinpact hydraulic. engine that is preferablymadeasva .unit adapted to be xedlin position .adjoining .the .shaftway or elevator well, .v either; horizontally or vertically, in-an -out-ofi-theway position where itoccupics little or 'no "'i1oor space.

:in: the best. form of my invention'this engine is connected bya system of conduits with a-supply of'iwater 'under head or pressure and also Withan `otake ondrain, semi-automatic valve'meansbe- .ing provided for controlling communication between said enginev and saidsupply and oftake :fand through which the movements of the car of thev apparatus `are controlled.

"It is Valsoa feature of my invention in its best form-rthatvthe-hydraulic' pressure f the water service of the building Within which=`the--appa ratus is installed is vutilized as thesource of power.

'Another'ffeatureiof =my invention is that the K:system-ofconduitsreferred to` includes a` supply Dumbwaiter apparatus of this type.

conduit ,fleading from the'waterxservice:ofnthe building to. said Valvemeansin which' supply con- 'duitsisf provided-r a. .check vva'lveithatv closesztow'ard said'waternservice. At .f a .1 point .between yf-said check valve .andr-said valvetmeans.isfconnected35 v 'oneendoanlauiiiliaryY supply conduit whichaextends to thebottomxof anaccumulatortank'ffrom which a :second g supply "of 'iwater' .under Ahead yior j pressure yis available for use at times in'voperating :the: engine.

Other features of .my invention:Larehereinafter rpointed out.

In @thea accompanying drawings: iFigure 1:.;isaaverticalfsectional:View*ofaiportion of a building equipped with .ia hydraulic-115 l.dumbwaiter ...apparatus constructed :int-accordance vwith* invention.

Figure 2 is a side elevation,i.partlyiinlsection, .'of the :upper portionoi the hydraulic engineunit A forming .part f :thefapparatus Itifllustrated tinfrgu flgel.

Figure 3 is a side'-elevation,.partlyzrinasectiom :oftheglower portion ofisaid unit.

#Figure e 4' fis: a fronteelevationf of ther portion xof the hydraulic engine unit illustratediin Fig.l2. 25

Jiguren 5 is ,afront elevation .of the .portionof thefhydraulic engine untillustrated in. Figz'3.

Figure 6 is a central longitudinalsectionalvview 'of Vthe threeeway :operating rvalve, llhereinafter :described rFigure' '1f-illustrates an Valternative/form ofilvalve :operating mechanism.

The:embo.diment ofrmy inventionfihereinillus trated includes a hydraulic engine :unit that vis -in- 1 dicatedsgen'era'lly :in "Fig, 1J at :l I fand hiatus-unit v"35 xcomprises: an :elongate-bed Iori fbar l I I with-which the other parts of the engine may -be permanently connected fandffby .means ofwhichf 'theeen'g'ine is fastened to fits1supporting iixture.k

InFig. 'f 1- the elevator-lapparatus'is' illustrated'`40 asprmfidedWithin a building* for servicebetween twoiloors of Athe latter and whenr the' elevatorzap.- 4para-tus 'is thus-installed within laiili'ildiiig the bar' I i maybexed .at its opposite. endstou'the frame f saidbuildingasfshown.

It is av feature of the present inventionthatthe zbar. II is a-length offchannel iron uponlthenner side .or i `1ace= .ot theweb .of Which-.is fastenedfas Xby v'screws Y I2, abracketr comprising 4@a-cylinder. =50 headf'l 3- that is. thel flower or intermediateportion -fofzfai'yoke whose; arms I4 .are :secured by screwsa I2 tofithe-Web of'. the'xchannelibar-TII. The/ucylinder head"`if3-isfformed lwith'e'a cylindrical threaded recess into which Visfscrewed the 'upperl exterio'rly 555 threaded end of a cylinder I6 consisting of a length of tubing, preferably brass.

At its lower end the cylinder I6 is telescopically and rmly fitted into a socket provided at the upper end of a yoke cylinder head I1 having a pair of integral legs I8 fastened by bolts I9 to the inner face of the web of the channel bar I I. The head I1 comprises two concentric circular walls 20 and 2| which provide between them an annular trap chamber 22 communicating at its upper end with the interior of cylinder I6 and which is closed at its lower end by a bottom wall 23.

Within the cylinder I6 is a piston head 24 that is fixed rigidly to the upper end of a tubular piston rod 25 which extends downwardly through the central aperture of the cylinder trap head i1 to the exterior of the latter. Fixed to the lower end of the tubularlpiston rod 25 is a sheave-carrying yoke 26 including an intermediate hub portion 21 fast on piston rod 25 and a pair of depending arms or side frames 28, Fig. 5, by which the axle 29 of a sheave 39 is supported in a position parallel with the web of the channel bar I I.

The depending arms 28 of yoke 26 also support the axle 3l of a truck 32 which bears against the inner side or face of the web of the channel bar II and is adapted to roll thereon thus providing lateral support for the free end of the piston rod, particularly when the latter is near the limit of its outward movement. The outer sides of the depending arms 28 of the yoke 26 ts snugly against the inner faces of the flanges of the channel bar II but are free to move longitudinally relatively thereto.

Above lthe sheave 30 the yoke 26 is provided with a cross bar 33 to which may be fastened one end of a wire cable 34.

Between the upwardly extending arms I4 of the head I3 is arranged a sheave 35 that is rotatably supported by an axle 36 mounted at its opposite ends inthe arms I4 of the yoke.

The wire cable 34 extends from the bar 33 of yoke 26,Y Fig. 3, to and over the sheave 35, Fig. 2, thence downwardly to and around the sheave 36, Fig. 3. From the sheave 36, cable 34 extends upwardly within the channel bar I I,through the oor F of the building, to and around guide sheaves 36 and 31, and thence downwardly to the car 38 of the apparatus to which its other end is fastened.

The car 38 is movable vertically within a shaftway or well 39 at opposite sides of which are provided rails 40 by which the car is guided as it is moved vertically.

The sheaves 36 and 31 are mounted upon a crossbar or framework 4I provided at the tops of the rails 40.

Sometimes two sheaves are mounted on axle 29 in which case the end of cable 34, instead of being fastened to cross-bar 33, is carried around the second or added pulley and fastened at its end to an eye 84 provided on the lower head I1. This arrangement would give a four to one ratio between the movement of yoke 26 and the movement of the car. The construction illustrated which employs a single sheave 30 gives a three to one ratio.

The upper head I3 of the cylinder is formed with a cored port 42, one end of which communicates with the upper end of cylinder I6 and the opposite end of which is connected by a pipe 43 with a port 44 provided in the body 45 of a threeway valve that is indicated generally at 46. Figs. 2, 4 and 6. The body 45 of this three-way valve `inay be embraced by a clamp 41 by means of which it is fastened rigidly to the cylinder I6. The body 45 is made with an inlet port 48, Fig. 6, that is connected by a conduit with a pipe 49 that is part of the water service system of the building within which the elevator apparatus is arranged. This conduit includes pipes 56, I and 52 and also a check valve 53 which closes toward the service pipe 49. I herein provide an accumulator tank 54 which may be entirely closed and air tight except for a port at its bottom connected by a pipe 55 with the conduit 50- 5I-52-53 at a point between check valve 53 and three-way valve 46. The tank 54 is incorporated in the apparatus in an empty condition, except for air, and when a supply of water from the water service pipe 49 is available, it will rise through the pipe 52, check valve 53, and pipes 5I and 55 into the accumulator tank 54, and the air that is within the latter may be compressed by the water that forces its way into said tank.

When the tank 54 is air tight the air under compression therein supplies water to the engine under pressure sufficient to operate the latter. When said tank 54 is not a closed air tight tank then it will be located in an elevated position within the range of the head of the water service system but at suiflcient height to supply water to the engine under enough head to operate the engine.

Fixed within the body 45 of the three-way valve 46 is a tubular lining or bushing 56 within which is arranged a valve member that is indicated generally at 51. At its upper end this valve member is pivotally connected to the lower end of a link 58 whose upper end is pivotally connected with one arm of a lever 59, Fig. 4, that is fulcrumed at 6D upon an arm 6I forming part of the head I3. The other arm of lever 59 is pivotally connected at 62 to a vertically disposed shipper rod 63 that is slidably mounted adjacent to its lower end in a bearing provided in an arm 64 projecting from the channel bar II.

As herein shown the shipper rod 63 is moved endwise manually to adjust the valve member 51 to start the movement of piston 24 in one direction or the other, and as the piston nears the limit of its movement in that direction, an arm 65 forming part of the yoke 25 engages either the collar 66 or the collar 16 which acts through rod 63, lever 59 and link 58, to return valve member 51 to its intermediate position thereby interrupting the passage of water to and from the cylinder I1 and stopping movement of piston 24.

The outer end portion of this arm 65 is formed with a vertical hole that is loosely occupied by the shipper rod 63, and as the piston nears the limit of its downward movement said arm engages the collar 66 fast on shipper rod 63 and moves the latter downwardly until the valve element 51 reaches its intermediate position and shuts off the supply of water to the cylinder.

When the piston 24 is to be driven upwardly the shipper rod 63 is manually depressed or lowered beyond the position to which it was moved by the arm 65 which adjusts the valve member 51 from its intermediate position into a position where the upper end of the cylinder I6 is connected with an oiftake conduit including a pipe 61. This pipe 61 has its upper end connected with the lower end of the body 45 of the threeway valve while its lower end is connected with the drain pipe 68 of the building.

When the upper end of the cylinder I6 is thus connected with the off-take pipe 61, the weight of the car 38 carries the latter downwardly and it `actsi throu'gh the 4cable-34 to raise 'thepiston 24.

"Ihisdownwardmovementof the car-'is regulated .-andcontrolled by the water. that l isfdisplaced #from the upper end `of cylinder.` l 6. .by` the upward emot/ementl of the-piston 24.

Near its `lowerend. the body-45 -of the threeway valveis made..with-an annular chamber1l69 f surrounding the tubulary bushing .256, r the l latter v.being made...with radiall vports 1l)Y extendingv from the interior-ofbushingj55 to said annular cham- Just yabove the annular chamber 69, thebody .'45 of the three-way valveis -alsolformed.;with another l.annular chamber 14 surrounding s the "bushing -56 .through which saidvbushingI exl-tends, and withinthis chamber .14 the said-bushing is made with radial ports 'I5-which always connect the .portion ofthe interior ofbushing 56 which is between thevalve pistons 1 l and 12 .with

thev annularchamber 14. -This annular chamber V'I4 communicates .with one end of the supply pipe section 59-so that the chamber y14 -is continuously in communication vwith the water supply -gpipe and -is lled with water. undersubstan- `ti'ally the same-head or pressure Vwhichlexists Awithin `water-service -pipe 49,- or accumulator tank 54.

The `valve .member51 is constructed-with three valve pistons 1i, 12 and 13, and the valve piston 1I valways occupies a position above. the ports-15 `rwhile the valve piston`12 always occupies-a position below the ports 15. Therefore, the pressure #effects ofI the-water that is within the bushing 56 vpower piston 24 of the engine is'at rest and this is the condition of the valve member while the power piston 24 remains at the limit of itsstroke in either direction. or stationed at any intermediate position.

When. the v.shipper rod 63, Fig. 4, is manually shoved ldownwardly to start the. powenpiston :24 upon its upward stroke it acts throughthe .lever v59 to raise the valve member 51. until the .piston 13 is above the ports 19, Fig. 6. Whensaidvalve piston occupies this position communicationexists between the lower end ofthe to and from pipe 43 and the oiftake pipe 61 so that as thezpiston 24 is raised by the weight of the oar, the lwater above said piston is discharged from cylinder IG through pipe 43 into the annular chamber .B9 from which it passes through ports and thence downwardly through the offtake pipel'.

`As the power piston 24 nears the limit of its Y ,upward movement its arm 65, Fig. 3, engages the collar fast on shipper rod 53 and raises the latter. As the shipper rod 63 is thus lifted, it lacts through the lever-59 tozlower the valve element 51 until it occupies its intermediate position shown in Fig. 6 which stops further movement of the power piston.

v'I'he power piston 24 is started upon its down-' ward travel by manually raising the shipper rod 1.63 .which acts throughlever59 to Ilower thevalve member 51 `to a pointwhere thevalveipiston 12.1is

.below ktheports'f'1 0 of .the bushing56. LiThisestabolishes communication; :betweenflthe: pipe 43:@and

L supply .pipe-section 5I)A viathe 'interior of bushing Q56 and the:.annular chamber'14. 7lXli/Taterunder `.pressure thenfnowsi from supply. pipe.section-50;4

I.'through.the-valve body 45,. pipe243fand the-:cored 1 .porti42,f1ig.22,v into the cylinder 'IB'..at the .upper .1 end thereof.`

'thepower .piston` 24 nears'V theu limitsofwits odownward movement itis auton'iatically:stoppedgy cas-.above :described by the engagement of .arm265 A .with `collart'. Inthis Awaythe control'of the `.apparatus :is semi-automatic, the V.power piston being manually startedupon .its travel in-:either lfdirection and .automatically stopped cvs/hen 1 it reaches the limit of its-movement infthatLdirection.

.The interior .of the cylinder. I6 that Ais below lthe power. piston 24 is always in communicationzwith the .interior of the4 tubular piston. rod 25/throughfg20 ports 11 provided in said .piston rod near the .upper end: thereof, Vwhile' the interior. of the :lowerf -end .portion ofthe piston rod always communicates with the outsideatmosphere through `ports '18 formed insaid piston. rod near. the. lower end;A

. thereof. 7'Itwill thus be clear that ther air that. is within cylinder I6 below 4power piston.24 fisfree to pass into and out of said. cylinderzwithoutfretarding materially thenmovements` off saidxpiston and this is a feature -of vthis invention.

fIt is also a desirable feature. of. this; invention that the ports "are disposedinear the power pisthe latter reaches the limit of its downward .move-.1.

.Y ment thessaidports 11 enter within'. the circular wall Ziandzare closed thereby providing a-cushioning stop for the downward movement of the piston.

The, trap chamber r 22 is provided'y at"l the` lower? end of-@cyl-inder I6 to catch any waterthatpmay `succeed inleaking past .the power piston-124 from thev upper end .of the cylinder, .and said cham- ;.ber is provided adjacentato its .bottom with. an

outletA that issconnected .by a drain pipe 19 with oiftake `pipei` and drain-pipe 68 of the building.

Whatever Awater .tends to accumulate .withinthe .trap chambers 22. and 82 iiows away by. gravity through their outlets and pipes V'I9 and83. As a .resultwofathis' construction it. is impossible, when :allijointszare ingood condition, for 1water to leak outof the apparatus otherwise thanvia the drain Jpipe] 9.

It will be. clear from the `above description that when the Ahydraulic engine Il] is disposed infa, 4verticalyposition as. shown, the weight of :the power piston and parts connected therewith .serves to. counterbalance, .in part, the weight of the car 38 :and its load.

' Also, the apparatus herein illustrated is par-A ticularly constructed to utilize the .water ofithe .Water supply service .ofV a building withinwwhich' theapparatus' is arranged and it4 isaifactthat useoffwater-on the various' floors of the'building Will cause they pressureA of s the-*water withinf:the-W5 service pipe 49 to vary considerably. The purpose, therefore, in providing the accumulator tank 54 is to compensate for variations of the water pressure within the lower end of the pipe 55. When the pressure or head within service pipe 49 is below normal the check valve 53 will automatically be maintained closed and the hydraulic engine will be served with water from the accumulator tank 59. When, however, the water pressure withinthe service'pipe 49 is raised or restored to normal through reduction in the use of water in other parts of the building, Water will flow upwardly from service pipe 49 past check valve 53 and upwardly through pipe 55 into tank 54 thereby replenishing the supply of water within the latter.

The collar 95 near the lower end of the shipper rod 63 is provided with a handle 89 by means of which said rod may conveniently be operated by a person on the lower oor. At its upper end, and above the floor F, the shipper bar 63 is provided with another handle 8i by means of which a person on the upper iloor may conveniently operate said shipper rod.

From the above description it will be seen that I have provided an inexpensive and eilicient selfcontained portable dumbwaiter apparatus which can be conveniently transferred to and quickly installed in a new or existing building, and it is a feature of this invention that this dumbwaiter apparatus includes a compact, self-contained, hydraulic engine mounted upon a base-bar which is preferably a metal channel bar, said engine being adapted to be installed either in a vertical position close to the shaftway or elevator well where it occupies little space, or horizontally immediately below the ceiling where it will occupy no floor space.

It will also be seen that this hydraulic engine including its operating valve 4B, its automatic terminal stop mechanism; and the shipper mechanism, are permanently assembled on the channel bar as a complete self-contained power unit ready for installation which can be connected with the car of an existing manually operated dumbwaiter and with the water service of the building at comparatively small expense.

My new dumbwaiter apparatus is small and convenient in its construction and operation and costs very little to operate and maintain.

The lifting capacity of the above described apparatus is limited to the maximum effort of the water pressure and in case of obstruction to the ascent of the car no breakage of cable or machine will result because of the limited lifting effort applied to the car, and to the obstruction, thus avoiding shut down or serious damage.

In the descent of the car the plunger is overhauled by the weight of the car and load. Should the car be obstructed by misplacement of load, or otherwise, the hoist cables do not slacken or come oi of the leading sheaves and the car cannot drop. In case of obstruction the downward effort on the car is less than the weight of car and load as the moving parts of the hydraulic engine serve as a partial counterweight.

As will be clear the self-contained hydraulic engine unit can be readily installed to operate existing hand operated dumbwaiters. It is calculated that three sizes of engines and two roping ratios at the engine, will meet practically all pressure and load requirements when the apparatus is installed for use in connection with th water service system of a building.

As will be clear to those skilled in this art an electric push button control system may, if desired, be substituted for the above described direct manually operated control mechanism for the three-way valve. It will also be clear that it is not essential that the valve means be embodied in a single three-way valve unit.

Any leakage of water past the lower valve piston 13, Fig. 6, is conducted away through the drain pipe 91, while the upper end of the body 45 of the three-way valve is made with a cup 82 to receive any water which may leak past the upper valve piston 1|. As this water collects within the cup 82 it ilows by gravity from the latter through pipe 83 and drain pipe 6l to the drain pipe 68 of the drainage system of the building.

It will be clear from the above description that the accumulator tank 54 holds a reserve supply of water under head or pressure which is automatically delivered to the apparatus when the head or pressure of the water within the service pipe 49 falls below normal through excessive use of water in other parts of the building or for other reasons. When this accumulator tank 54 is an open tank, it will be disposed in an elevated position within the range of the head or pressure of the water within service pipe 49 but when the tank 54 is a closed and air tight tank, it may be positioned lower than shown in the accompanying drawings, for example, within the room containing the hydraulic engine.

The control mechanism for valve 46 which includes the vertically movable rod 63 is operable by a person on either-hoor of the building at any time to start, stop and reverse the direction of movement of the car 38; In particular, when the car is at rest at the end of its movement in either direction, either operator may operate the bar 53 to start the motion of the car in the opposite direction.

In Fig. 7 I have shown a sending only control mechanism that is organized and arranged so that when the car is at the limit of its movement in either direction, only the operator on that floor of the building where the car is at rest can operate the valve to start the car on its travel toward the other loor. At the same time this mechanism is so constructed and organized that after the car has been started, and while it is in motion, either operator can stop the car at any point during its travel, and after the car has been thus stopped at an intermediate point either operator may cause the motion of the car to be resumed but only in a direction away from him. Thus the mechanism shown in Fig. 7 is what might be termed a sending only control mechanism.

Referring to Fig. '7 the arm 65 on the piston head cooperates with two abutments 86 and 8l provided upon a rod 88 slidably supported by the base member ll. Slidably mounted on the rod 88 is a sleeve 89 to which one arm of the lever 59 is pivotally connected, and below this sleeve 89 the rod 88 has fixed thereon an abutment collar 99.

The portion of the .rod 88 above the sleeve 99 is fitted telescopically and slidably within the lower end portion of a tube 9| that is supported in suitable bearings to move vertically. At opposite sides thereof the tube 9| is formed with longitudinal slots 92 occupied by studs 93 projecting from the rod 88. These slots equal to onehali of the total movement of the arm of lever 59 that is connected with sleeve 89.

Nea-r its lower end the rod 88 is connected with a hand lever 94 that is fulcrumed at 95 on any suitable support, while the tube 9| has asimilar hand lever 96 connected therewith fulcrumed at 91 on any suitable support. Stops 98 are provided to limit the swing ot the lever 94 and stops 99 are provided to limit the swing of the lever 99.

The parts of this mechanism are shown in the positions they occupy when the car is at the limit of its downward movement. At this time the arm 65 on the piston is against and beneath the abutment 86 so as to hold the collar 99 against the lower end of the sleeve 89 so as to hold lever 59 in its intermediate position, the upper end of the sleeve 89 then being in engagement with the lower end of the tube 9| with the pins 93 at the upper ends of slots 92.

With the parts in these positions the lever 59 can be operated only by upward movement of the rod 88 manually effected by means of the lower lever 94 and this upward movement of said rod acts through lever 59 to adjust the valve 46 so as to cause the car 38 to travel upwardly.

As the car 38 reaches the limit of its upward movement, the arm 65 on the piston engages the abutment 81 on rod 83 and moves the latter downwardly, said rod acting through pins 99 and tube 9| to swing the valve-operating lever 59 back into its intermediate position shown in Fig. 7 thereby shutting off the supply of water to the cylinder and stopping the car.

While the car is at the limit of its upward movement the lever 59 can only be operated by downward movement of tube 9| manually effected by means o-f the lever 96 since the arm S5 is then against abutment 8l.

It will thus be clear that when the car 33 is at the limit of its downward travel only the lever 94 can be operated to start the car. on its upward travel and that when the car is at the limit of its upward movement onlythe lever 96 can be operated to start the car upon its downward travel.

It should also be clear that while the car is in motion, it can be stopped by either lever 94 or 96 which at such times can also be utilized to start the car in a direction away from the lever that is operated.

What I claim is:

l. In a building, the combination with the gravity water service system thereof, of an elevator apparatus having, in combination, a vertically movable car; a hydraulic engine for operating said car disposed substantially below the level of the normal head of the water of said system so as to be operated thereby; a supply conduit through which water is delivered to said engine from the water service system of the building; valve means for controlling the passage of water to and from said engine and with which one end of said supply conduit is connected; a check valve in said supply conduit which closes toward said water system; an'auxliary emergency accumulator tank that is automatically loaded with a reserve supply of water from said water service system and a conduit connecting said accumulator tank with said first-mentioned supply conduit between said check valve and said valve means sothat when the water pressure of the water service system of the building falls below a predetermined point the engine is automatically supplied with water from said tank.

2. In a building, the combination with the gravity Water service system thereof, of an elevator apparatus having, in combination, a vertically movable car; a hydraulicvengine for operating said car disposed substantially below the level of the normal head of the water of said system so as to be operated thereby; a supply conduit through which water is delivered to said engine from the water service system of the building; valve means for controlling the passage of water to and from said engine and with which one end of said supply conduit is connected; a

check valve in said supply conduit which closes toward said water system; an air tight auxiliary emergency accumulator tank that is automatically loaded with a reserve supply of water from said water service system, and containing a body of air under compression, and a conduit connecting said accumulator tank with said rst-mentioned supply conduit between said check valve and said valve means, said tank occupying an elevated position adjacent to the level of the normal head of the water within said system.

3. In a hydraulic dumbwaiter apparatus of the character described, the combination with the valve means thereof, of mechanism for controlling and operating said valve means comprising a manually operated member accessible to a person on a lower oor of the building; a manually operated member accessible to a person on an upper floor of said building, and means connecting said members with said valve means so that operation of one member adjusts the other member and so that manual operation. of either member while the car of the apparatus is at rest at the limit of its movement in either direction is eiective only to start said car on its travel away from the floor of the building where both it and said member are located.

4. An elevator apparatus constructed in accordance with claim 3 wherein each of said members is manually operable to stop the car while the latter is in motion.

MARTIN B. MCLAUTHLIN. 

